Power Week: Solar Roadways – Sci-Fi or Future Reality?

A crowdfunding campaign to support the concept of "solar roadways" recently raised more than $2.2 million, surpassing its a $1 million goal (see video below). The concept, developed by electrical engineer Scott Brusaw, is based on specially engineered solar panels that are tough enough to be installed on roads and other surfaces -- like parking lots and sidewalks, etc. -- and that can theoretically pay for themselves through the generation of electricity.

The panels are said to be able to withstand up to 250,000-lb vehicles and can incorporate other features such as heating elements to eliminate snow and ice, and LEDs to provide road lines and signage. According to the company's calculations, if all the pavements and impervious surfaces in the 48 contiguous US states were covered with solar road panels, and assuming a daily average of four peak daylight hours, the total electricity generated would be almost 22 billion kWh.

A series of 4 W mini supplies from Recom operates over a temperature range of -40°C to +80°C. Measuring 36.7 x 27.2 x 17.1 mm, the RAC04-C/230 features short-circuit-protected outputs and are available in single 3.3, 5, 12, 15, or 24 V or dual 5/12, ±5, or ±12 V versions.

Intersil is offering new voltage options for its radiation-hardened family of ultra-low-noise, high-precision voltage references. The ISL71091SEH10, ISL71091SEH20, ISL71091SEH33, and ISL71091SEH40 are designed to enable better overall accuracy for 11 and 12 bit ADC resolution applications.

Würth Elektronik has expanded its line of wireless power coils with three transmitter coils and one receiver coil. The new transmitter coils comply with the WPC Qi standard, while the new receiver coil complies with both the WPC Qi and PMA standards.

International Rectifier has expanded its portfolio of StrongIRFET power MOSFETs targeting industrial applications. The 60 V devices come in a variety of through-hole and surface-mount packages, and offer low on-resistance, high current-carrying capability, a soft body diode, and 3 V typical threshold voltage. The company also introduced the M3G120 Series of 40 W radiation-hardened 120 V input DC/DC converters for satellite power systems.

A family of 20-W DC/DC converters from Artesyn has a 4:1 input range. The AXA series modules offer an input voltage range of 9 to 36 VDC and 18 to 75 VDC, and single outputs of 3.3, 5, 12, 15, and 24 V, as well as dual-output models providing ±12 and ±15 V.

Finally, new precision foil current sense resistors from Vishay Precision Group combine low TCR down to ±2 ppm/°C with power ratings up to 80 W. The S Series (SHR, SHS, SNR, and SPR) parts range in value from 0.002 Ω to 50 Ω with tolerances to ±0.1%.

I'm thinking that the best use for these materials is on roads / parking lots that get most of their use at night when there is no sunshine that would be shaded by the cars. They would also be best used in climates with lots of sun and little frost (in Connecticut we've not yet mastered paving roads with materials that can survive the winter). Finally, the segmented panels on highways will likely cause some road noise / resonance at high speeds that could be very annoying to drivers.

If the technology really works, is affordable, and is waterproof perhaps it should start being used on the rooftops of buildings and garages where the surface has continuous exposure to the sun and can avoid the stress of automobile traffic.

Regardless, it sounds like this will be feeding into the "grid" and not into batteries which would significantly increase the construction costs or inductive charging of cars (which would shade the tiles as they drove over.

Sanjib wrote, "the 'road' would get stolen if you do not keep guarding every 500 mtrs (or less) of the road!! How many guards you would need?"

Sanjib, that would be a problem in nearly every country. Keep in mind there are people in the U.S. who steal copper wiring because it's worth a few dollars. Imagine what stolen solar road panels would be worth to thieves!

I believe that you can also get "tiles" that look like cedar shake and possibly ones that have the look of the arcitectural asphalt shingles. It looks like you can get solar shingles tha tlook similar to the asphalt shingles but if the HOA is even specifying the colors that you are allowed to use, they porbably wouldn't pass (the pictures I saw they were significantly shinier than regular shingles)

Yet another reason to avoid neighborhoods with HOA covenants although it's getting harder to find...

@David Ashton: In most of the USA, the predominant roofing materials are shimgles. In my subdivision, that is literally the rule (HOA covenants). Even the color choices are limited to the ones originally offered by the developer. There have been allowances made for some new styles ("architectural" shingles that look a bit like tiles, with a 3D aspect) that were not around 15 years ago when development began. Tiles are mostly a Florida/California thing (Spanish-style barrel tiles). Even there that's mostly for up-scale houses.

@MHRackin....have a look at Crusty's links below, the tiles he links to are really quite good looking - not much different from roof slates. I know these are mostly used in the UK (from Welsh slate quarries) but there is no reason why the more usual roof tiles could not be built tlike this. In Australia a lot of roofs (mine included) use tiles - usually cement ones. A solar cell could be built into them without much trouble, I think?

Sharp used to have solar tiles, which I believe were to be used in place of typical asphalt shingles, rather than placed on top. Those dissappeared from their web site a few years ago. Now they are marketing "SunSnap" panels which have easier installation and integrated/available microinverters (EnPhase). http://www.sharpusa.com/SolarElectricity/SolarForResidential/SunSnap.aspx

I'm surprised nobody has brought up the legal impediments for roof solar. In my area (Atlanta) the building codes and the restrictions in nearly all HOA covenants explicitly forbid solar onstallations on roofs (for various reasons). This may date back to the days when roof solar meant hot water heating (either pool water or domestic ho water supply) when roof loading and leakage risk were the primary reason. The other mtoivation is esthetic, as a lot of the older technologies were fairly ugly!

Roof tiles would make a lot more sense. I think it's pretty easy to see that very little about the system makes any sense at all.

Even if the technology and economics were close to what would be viable, roof panels would still make a lot more sense. On a roof, you don't need to worrry about the surface neededing to hold weight, nor do you need to worry about the surface requiring traction.